asan: heap buffer overflow in _bfd_error_handler

[Alan Modra <amodra@gmail.com>]

On coff_slurp_symbol_table printing "unrecognized storage class"
for a symbol error.  If the symbol name is the last string in its
section and not terminated, we run off the end of the buffer.

	* coffgen.c (build_debug_section): Terminate the section with
	an extra 0.

diff --git a/bfd/coffgen.c b/bfd/coffgen.c
index 4d2b82e4a6f..90fba3b8554 100644
--- a/bfd/coffgen.c
+++ b/bfd/coffgen.c
@@ -1539,9 +1539,10 @@ build_debug_section (bfd *abfd, asection ** sect_return)
     return NULL;
 
   sec_size = sect->size;
-  debug_section = (char *) _bfd_alloc_and_read (abfd, sec_size, sec_size);
+  debug_section = (char *) _bfd_alloc_and_read (abfd, sec_size + 1, sec_size);
   if (debug_section == NULL)
     return NULL;
+  debug_section[sec_size] = 0;
 
   if (bfd_seek (abfd, position, SEEK_SET) != 0)
     return NULL;

-- 
Alan Modra
Australia Development Lab, IBM